What I mean is that moving the player dot off the screen causes the game to end. It would be nicer if movement off screen was prevented, or if maybe the screen wrapped around. I often would accidentally go off screen while trying to avoid a triangle, and the game would end unexpectedly. At the very least, the game should have something to warn the player that going off screen is game over.
There is a difference between gameplay that is unclear, and gameplay that is merely unknown. Learning things can be fun, but trying to learn through ambiguous, misleading experiences is not. Simply hiding the information your players need to understand the game will not make it more interesting. If anything, less.